For what it is worth the group photograph is the earlier of the two as it shows that he had served for three years in his regiment (what ever one it was) prior to the photograph being taken, whilst the one where he is on his own shows that he had served at least six years with his regiment with out a blemish on his record. Interestingly the first image shows that he was a Farrier & Shoeing Smith (trade badge on his sleeve) whilst the other one doesn't so one would assume that he had moved on from the trade that the badge represents. In both he is show with a driving crop as opposed to a short riding crop which, to me, would indicate that he would have had control of a team of horses rather than the one. Although his spurs can clearly be seen in the earlier image they can not be seen in the second one, however it would appear that he was wearing riding boots and not army boots when the second photograph was taken. Lastly the photograph of the group shows that he has one medal ribbon up whilst the in the second one he appears that he has two.